Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) is a frequently detected organophosphorus flame retardants (OPFRs) in various environmental media, and has been evidenced as reproductive toxicity. However, its adverse effects on spermatogenic cells are unknown. In this study, mouse spermatocyte GC-2spd (GC-2) cells were selected as an in vitro model, and the impact of mitochondrial structure and function, endoplasmic reticulum (ER) stress, cell apoptosis and the related molecular mechanisms were investigated. Our study indicated that cell viability was decreased significantly in a dose-dependent manner after TDCIPP treatment with the half lethal concentration (LC) at 82.8 μM, 50.0 μM and 39.6 μM for 24 h, 48 h and 72 h, respectively. An apoptosis was observed by Annexin V-FITC/PI stain. In addition, fragmentation of mitochondrial structure, an increase of mitochondrial membrane potential (MMP), reduction of cellular adenosine triphosphate (ATP) content, release of cytochrome c and activation of Caspase-3 and Caspase-9 activity implicated that Caspase-3 dependent mitochondrial pathway might play a key role in the process of GC-2 cell apoptosis. Furthermore, ER stress induction was convinced by altered morphology of ER and up-regulation of ER targeting genes, including (Bip, eIF2α, ATF4, XBP1, CHOP, ATF6 and Caspase-12). Taken together, these results demonstrate that both mitochondrial apoptotic pathways and ER stress apoptotic pathways might play important roles in the process of apoptosis in GC-2 cells induced by TDCIPP treatment. Therefore, the potential reproductive toxicity of TDCIPP should not be ignored.

中文翻译：

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磷酸三(1,3-二氯-2-丙基)酯诱导小鼠精母细胞GC-2细胞内质网应激和线粒体依赖性细胞凋亡

磷酸三(1,3-二氯-2-丙基)酯(TDCIPP)是一种在各种环境介质中经常检测到的有机磷阻燃剂(OPFR)，并已被证明具有生殖毒性。然而，其对生精细胞的不利影响尚不清楚。本研究选择小鼠精母细胞GC-2spd（GC-2）细胞作为体外模型，探讨线粒体结构与功能、内质网（ER）应激、细胞凋亡的影响及其相关分子机制。我们的研究表明，半数致死浓度（LC）分别为82.8μM、50.0μM和39.6μM的TDCIPP处理24小时、48小时和72小时后，细胞活力以剂量依赖性方式显着降低。通过Annexin V-FITC/PI染色观察细胞凋亡。此外，线粒体结构的断裂、线粒体膜电位 (MMP) 的增加、细胞三磷酸腺苷 (ATP) 含量的减少、细胞色素 c 的释放以及 Caspase-3 和 Caspase-9 活性的激活表明 Caspase-3 依赖性线粒体该通路可能在GC-2细胞凋亡过程中发挥关键作用。此外，内质网应激诱导是通过内质网形态的改变和内质网靶向基因（包括Bip、eIF2α、ATF4、XBP1、CHOP、ATF6和Caspase-12）的上调来证实的。综上所述，这些结果表明线粒体凋亡途径和内质网应激凋亡途径可能在TDCIPP处理诱导的GC-2细胞凋亡过程中发挥重要作用。因此，TDCIPP潜在的生殖毒性不容忽视。